Origin

The earliest sense of radical is ‘having to do with the basic nature of something, fundamental’, and it goes back to Latin radix ‘root’, the source also of eradicate (Late Middle English) ‘to root out’ and radish (Old English), and related to root. In political terms, a radical is someone who wants complete political or social reform—to be achieved by going to the root of the problem. In the 1970s, the American writer Tom Wolfe coined radical chic for a fashionable affectation of radical left-wing views.